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United States Patent | 5,300,902 |
Satoh ,   et al. | April 5, 1994 |
A surface acoustic wave device comprises a pair of multiple-electrode surface acoustic wave elements that are mirror-symmetrically arranged and disposed on a piezoelectric substrate. Each of the multiple-electrode surface acoustic wave elements comprises a plurality of input/output inter-digital transducers and connected inter-digital transducers. The number of the input/output inter-digital transducers is equal to or smaller by one, than the number of the connected inter-digital transducers, so that insertion loss of the surface acoustic wave device can be reduced without increasing the size of the device.
Inventors: | Satoh; Yoshio (Kawasaki, JP); Miyashita; Tsutomu (Kawasaki, JP); Ikata; Osamu (Kawasaki, JP); Takamatsu; Mitsuo (Kawasaki, JP); Matsuda; Takashi (Kawasaki, JP) |
Assignee: | Fujitsu Limited (Kawasaki, JP) |
Appl. No.: | 850835 |
Filed: | March 13, 1992 |
Mar 29, 1991[JP] | 3-066119 | |
Aug 28, 1991[JP] | 3-217432 |
Current U.S. Class: | 333/193; 310/313R; 333/195 |
Intern'l Class: | H03H 009/64 |
Field of Search: | 333/193,195,194 310/313 R,313 B,313 C,313 D |
4468642 | Aug., 1984 | Hikita | 333/193. |
4492940 | Jan., 1985 | Hikita | 333/195. |
4939487 | Jul., 1990 | Yuhara et al. | 310/313. |
5087901 | Feb., 1992 | Kurosawa et al. | 333/196. |
5130681 | Jul., 1992 | Ohnuki et al. | 310/313. |
Foreign Patent Documents | |||
60-59809 | Apr., 1985 | JP. | |
231417 | Sep., 1989 | JP | 333/193. |
2-202710 | Aug., 1990 | JP. | |
3-270309 | Dec., 1991 | JP. |
M. Hikita et al., "High performance SAW filters with several new technologies for cellular radio," IEEE 1984 Ultrasonics Symposium, vol. 1, Nov. 16, 1984, Dallas, Tex., pp. 82-92. M. Lewis "SAW Filters Employing Interdigitated Interdigital Transducers, IIDT" Ultrasonics Symposium Proceedings, circa 1982 (pp. 12-17). M. Hikita et al. "800 MHz Low Loss SAW Filter". Institute of Electronics, Information and Communication Engineerings of Japan Technical Study Report, US81-22 (pp. 25-31), circa 1981. M. Sakamoto et al. "Surface Acoustic Wave (SAW) Filter" Electronics Material, May, 1988, (pp. 120-124). |